Uncaught TypeError: Cannot read property 'value' of undefined

function deleterow(id){
    document.form1.elements['del[]'][id].value = 1
    count_del_price()
    document.getElementById("tr"+id).style.display = 'none'
}

function count_del_price(){
    priceminus = 0;
    inputCount = document.form1.elements['del[]'].length //document.form1.elements['tcounter'].value
    for(i=0; i<=inputCount; i++){
        if(document.form1.elements['del[]'][i].value == 1){// Uncaught TypeError: Cannot read property 'value' of undefined 
            priceminus += parseFloat(document.form1.elements['price[]'][i].value) * parseFloat(document.form1.elements['qty[]'][i].value);
        }
    }
}

Code (markup):

I am getting "Uncaught TypeError: Cannot read property 'value' of undefined" error in if statement. if part of the code never executes. What's wrong I am doing here. Please help.

 

Can you post the HTML code associated with this script?

 

document.form1
requires that your form has name="form1"

I suspect that you just have an id="form1" there? In that case either add the name tag or use
document.getElementById('form1')

 

In this line

for(i=0; i <= inputCount; i++){

Code (markup):

I can't say for sure, since I haven't seen your HTML code, but I think the problem is the less-than-or-equal-to comparison operator in that line.
Try changing that to a less-than comparison operator.

for(i=0; i < inputCount; i++){

Code (markup):

The reason it's doing that is because you're going one higher than what exists on the page.


--------------------------


Let me show you an example. Take this code.

var array = ['a', 'b', 'c'];

Code (markup):

It has a length of 3, but it's highest index is 2 because arrays' indexes start at 0.

So if you were to do this code (similar to what you did)

for (var i = 0; i <= array.length; i++) {
    alert( array[i] );
}

Code (markup):

The last alert value would be undefined because the loop is allowed to run while 'i' and 'array.length' are the same,
which means you will be trying to access array[3] which doesn't exist; only 0, 1, and 2 exist.

Hope that helps.